1. Technical Field of the Invention
The present invention relates in general to mobile telecommunication services, and in particular to reservation and allocation of voice channels in a congested mobile telecommunications system.
2. Description of Related Art
Initially, mobile telecommunications systems were designed primarily for purposes of enabling voice communications in a wireless environment. As wireless telecommunications systems have evolved, additional voice and messaging services and features have been added. In addition, newer generations of wireless telecommunications systems are being designed to further handle a diverse range of data communications services. Generally, such newer generation systems include both a circuit-switched network that is used for voice communications and a packet-switched network that is used for data communications.
For example, third generation GSM standards provide for a general packet radio service (GPRS) network that is integrated into or over-laid on a circuit-switched network. Other types of wireless packet data networks include cellular digital packet data (CDPD) and IS-95 Data. Using a mobile telephone that is capable of communicating in both a circuit-switched mode or a packet-switched mode, a cellular subscriber has access to both voice and data communication services. A telephone that supports wireless application protocol (WAP), for instance, allows for both types of communications and also provides a wireless telephony application (WTA) interface that permits interaction between packet-based and circuit-based services within the mobile telephone.
As usage of mobile telephones for voice communications continues to expand, cellular systems are frequently experiencing severe congestion during busy call hours. This problem is exaggerated by billing schemes that offer subscribers free (or reduced rate) night and weekend calling. As a result of these free calling schemes, talk times tend to increase dramatically, thereby prolonging periods of congestion.
When a cellular subscriber encounters congestion in the circuit-switched network, his or her call request or other service request is typically rejected because the system does not have sufficient capacity to handle the request. The subscriber can continue re-sending the request until a voice channel becomes available or can wait until a later time when the system is no longer congested. These options, however, can be time-consuming and frustrating. In some cases, the network might use a directed retry procedure in an attempt to obtain a voice channel in an adjacent cell. Such a procedure, however, is not always successful.
Finally, subscribers can obtain special priorities on a subscription basis. In other words, a subscriber might be able to pay extra monthly fees to obtain service access priorities as compared with subscribers that have a standard subscription agreement. Such special priorities might increase the subscriber""s chances of accessing the network during busy periods, but they generally would not provide access to the network at times when there simply are no voice channels available. Moreover, such special priorities are static (i.e., they must be paid for and established on a subscription basis rather than on a per call basis). If an intended call was not of particular importance, the subscriber might want to manually try the call at a later time. A static priority system does not provide that option. On the other hand, a subscriber might also have an emergency in which case he wants to be able to obtain access to the system as soon as possible. Unless the subscriber previously negotiated a special priority, however, he will not be able to obtain any priority during the emergency situation.
There is a need, therefore, for a system and method for assigning priority in a cellular system on a per call or per service request basis. Preferably, such a system and method would allow a subscriber, when the network is congested, to request priority for a particular call request and to further perform such a priority request using a minimal amount of the already scarce network resources. In exchange, the subscriber could be charged a service fee, or the call, once connected, could be charged at a premium rate. This would allow a mobile telecommunications system operator to increase the number of available services and to generate additional revenue.
The present invention comprises a method and system for reserving radio channels in a mobile telecommunications network. A mobile station operating in the network requests that a radio channel be reserved for its use by transmitting an immediate call reservation (ICR) service request. In response, the network subsequently identifies an idle radio channel that can be accessed by the mobile station. The network then reserves the idle radio channel for use by the mobile station.
In accordance with one embodiment of the invention, one network is used for voice communications and another network is used for the ICR service request. An initial radio access attempt is performed on a first network, such as a circuit-switched network. Responsive to failure of that attempt, the ICR request is transmitted via a second network, such as a packet-switched network, thereby avoiding additional congestion in the first network. The second network then performs much of the necessary processing of the ICR service request and interacts with the first network to perform the requested radio channel reservation.
In accordance with another embodiment of the invention, a list of mobile stations that are awaiting access to radio channels is stored in the mobile telecommunications network. The list serves as a queue of mobile stations that have submitted an ICR service request. As radio channels become available, each radio channel is allocated for use by one of the mobile stations on the ICR list.
In accordance with yet another embodiment of the invention, the mobile telecommunications system includes a circuit-switched network, a packet-switched network, and a service platform. The service platform interfaces with both the circuit-switched network and the packet-switched network. The service platform receives ICR service requests via the packet-switched network and, in response, initiates a reservation of a radio channel in the circuit-switched network for use by the mobile station.